The Psychiatric Imaging Laboratory at the Brigham and Women's Hospital (Dr. Shenton, Director;PI, NIMH R01 5R01MH050740-13), in collaboration with the ICOHRTA Research Training Program in International Mental Health &Developmental Disabilities (MH/DD) at the Children's Hospital Boston (Dr. Munir;PI;Fogarty D43 TW005807), is applying for an International Research Collaboration - Behavioral, Social Sciences (FIRCA-BSS) [R03] grant for Dr. Ozgur Oner of Ankara Diskapi Children's Hospital in Turkey. Dr. Oner has been a highly successful international ICOHRTA fellow. The research goal of this proposal is to facilitate the further development of collaborative research between NIH supported U.S. biomedical scientists and investigators in Turkey, a FIRCA eligible country. The scientific objectives include: (1) studies of prefrontal, hippocampus-amygdala, caudate and superior temporal gyrus volumes measured by Magnetic Resonance Imaging (MRI) in adult subjects with schizophrenia and their "high-risk" (HR) first-degree relatives, stratified with and without ADHD, compared to subjects with ADHD, and normal controls;and (2) studies of the relation of neuropsychological executive, and attentional characteristics with the aforementioned brain structures in each group. Previous studies have shown that HR relatives of subjects with schizophrenia have attentional problems predictive of the emergence of schizophrenia, which are concomitant with structural and functional brain abnormalities and dysregulation in the dopaminergic systems, which may, in turn, involve the presence of symptoms resembling the ADHD phenotype. Subjects with ADHD themselves present with functional and structural brain variations, particularly in right prefrontal cortex and caudate, and may have dopaminergic transmission abnormalities, as reflected by imaging and genetics studies. We will study 4 groups: (i) index subjects with DSM-IV schizophrenia (n=30);(ii) their non-psychotic first-degree relatives --the high-risk HR group stratified as HR with ADHD (HR-A) (n=20) and without HR-NA (n=20) DSM-IV ADHD;(iii) subjects with DSM-IV ADHD (n=30);and (iv) normal controls of similar age, gender, and parental education (n=30). Weschler Adult Intelligence Scale-Revised, Wisconsin Card Sorting Test, Trailmaking Test A and B, Continuous Performance Test, and Weschler Memory Scale will be used to evaluate executive, memory and attention functions. The proposed study aims involve innovative approaches in comparative schizophrenia and ADHD risk research, as well as use of neuroimaging and psychological research methodologies and expertise under the direction of a leading center in the US that supports and builds upon already established and productive international research collaboration in Turkey. 7. PUBLIC HEALTH RELEVANCE: The proposed aims will provide access for a promising international investigator to new perspectives, innovative concepts and technologies in neuroimaging at a leading NIH supported US center. The proposed study will investigate important scientific topics relevant to global health, schizophrenia and ADHD, both of which cause significant burden on society globally.